How To Concatenate Strings In Java

StringBuilder and StringBuffer classes can be used to concatenate strings. The difference between the two is that StringBuffer is thread-safe while
StringBuilder is not. In practice you will be using StringBuilder most of the
time.

public static void main(String[] args) {

StringBuilder builder=new StringBuilder();
builder.append("ONE");
builder.append(" TWO");
builder.append(" THREE");

System.out.println("Concated :"+builder.toString());

StringBuffer buffer=new StringBuffer();
buffer.append("FOUR");
buffer.append(" FIVE");
buffer.append(" SIX");

System.out.println("Concated2 :"+buffer.toString());

}